The increase in fatigue to failure (FTF) cycles by three times was observed for styrene-butadiene rubber (SBR) vulcanizate containing carbon black treated with 2.73 phr vinyltriethoxysilane (VTEOS) over the untreated furnace carbon black (UFCB) vulcanizate at an extension ratio of 1.80. There could be several factors responsible for such a phenomenal increases in FTF; however, specifically the chemical reactions associated with this are investigated. The UFCB contains carboxylic and lactone groups on its surface besides other groups. On treatment with VTEOS, the ethoxy or silanol group(s) of it reacts with the carboxylic and lactone groups of UFCB. This provides an interface between the particulate UFCB and the flexible rubber matrix unlike UFCB, which adsorbs polymer in absence of VTEOS, Furthermore, the vinyl group thus attached to the UFCB takes part in vulcanization reaction and increase in the degree of cross-linking. In addition, the VTEOS substantially reduces the formations of weak polysulphidic linkages. The added flexible interface increased cross-linking and reduced polysulphidic linkages seem to be mainly responsible to the significant improvement of FTF behavior.